1. Field of the Invention
The present invention relates to a rotatable vent having an annular rotatable louvered panel and an underlying rotatable impeller both of which are rotatably positioned with respect to a fixed shaft. More specifically, it relates to such a louvered panel which cooperates with a fixed collar to define an air flow passageway while resisting undesired entry of precipitation into the building to which it is secured.
2. Description of the Prior Art
It has been known to provide various types of turbine and other vents which are secured to roof portions or other portions of a building for purposes of efficiently exhausting air from the building and discharging the same to the surrounding environment.
In some such structures a motor or solar energy source of power is employed to energize a rotating fan element which has suitable blades for exhausting air from a region. The rotating fan which is fixedly secured to a shaft and exhausted through a cover member may be provided with a series of louvers.
It has also been known to provide turbines which are freely rotatable by wind currents to rotate an exhaust assembly and draw air up through a collar and outwardly through a passageway. See, for example, U.S. Pat. No. 4,641,571.
U.S. Pat. No. 5,779,539 discloses a static venting system which had a plurality of nested louvered members providing a static venting system for discharge of air therethrough.
One of the disadvantages of prior art systems is the need to have a source of energy to power the same or the need to rely on air flow through a static system.
Another disadvantage of prior art systems has been the large generally dome shaped aesthetically unpleasant appearance of the louvered element which projects a substantial distance above the roof or other structure.
A further disadvantage of prior systems involves collar members which are so closely placed to the rotating louver members that under certain conditions undesired contact therebetween produced an unpleasant noise during relative rotation.
Also lacking in prior art systems are structures of suitable strength as to withstand extended use under varying weather conditions, including wind loading.
In spite of the foregoing there remains a very real and substantial need for an improved rotatable vent which is devoid of prior inadequacies.